Based on light and scanning electron microscopical studies, three new gonad-infecting species of Philometra Costa, 1845 (Nematoda: Philometridae) are described from marine fishes of the genus Lutjanus Bloch (Perciformes: Lutjanidae) in the northern Gulf of Mexico: P. longispicula sp. n. from the ovary of the northern red snapper L. campechanus (Poey) (type host) and silk snapper L. vivanus (Cuvier); P. latispicula sp. n. from the ovary and rarely testes of the grey snapper L. griseus (Linnaeus); and P. synagridis sp. n. (only males available) from the ovary of the lane snapper Lutjanus synagris (Linnaeus). These species are mainly characterised by the lengths of spicules (378-690 µm, 135-144 µm and 186-219 µm, respectively) and spicule shapes, structure of the distal portion of the gubernaculum and the structure of the male caudal end. These are the first valid, nominal species of gonad-infecting philometrids reported from fishes of the family Lutjanidae in the western Atlantic region.